Summary
We present a hybrid imaging methodology, denominated multiharmonic electrical impedance tomography (MH‐EIT), which leverages the nonlinear dynamic response of breathing‐damage types in order to achieve enhanced imaging performance. Certain structural damage at their incipient stage, such as cracks and delaminations, exhibit a characteristic nonlinear dynamic response when probed by ultrasonic waves. Such response is rich in nonlinear harmonics of either integer or fractional order. The MH‐EIT method probes the domain of interest by using both ultrasonic and electrical stimuli and leverages the coupled electromechanical nonlinear response to improve the conditioning of the inverse tomographic problem, which ultimately results in enhanced image resolution and/or decreased number of sensors. Contrarily to traditional EIT, where only a single dataset can be acquired for each sensor pair, the multiharmonic approach enables the measurement of multiple linearly independent datasets at any given sensor pair. The paper presents the theoretical and numerical frameworks to implement the MH‐EIT methodology as well as a numerical assessment of the capabilities and advantages provided over traditional EIT methods.